The density of radioactive tritium in samples of seawater from near the Fukushima No. 1 nuclear plant doubled over 10 days to hit a record 1,100 becquerels per liter, possibly indicating contaminated groundwater is seeping into the Pacific, Tokyo Electric Power Co. said.

The density of radioactive tritium in samples of seawater from near the Fukushima No. 1 nuclear plant doubled over 10 days to hit a record 1,100 becquerels per liter, possibly indicating contaminated groundwater is seeping into the Pacific, Tokyo Electric Power Co. said.

Strontium-90 has a half life of about a quarter of a century. So, not particularly nice for life in general for about a hundred years (at which point the radioactive strength of the strontium-90 will be 1/16 of what it is now). And, of course, all the while it will be presumably diluting in the ocean in any event. So, the radiative concentration by volume of carrying medium will be far less than 1/16 of what is it now in a hundred years. I do concede, though, that last point might need significant qualification due to potential concentration up the food chain.